Home – Home – Jornals – Russian Geology and Geophysics 2018 number Неопубликованное

Last decades it has been shown that additional information about the structure and composition of rocks can be extracted from time domain induced polarization (IP) studying the transient characteristics of IP in a large time range from 1 ms to 10 s or more. In this paper compare field IP data obtained on the Yasnoe gold deposit (Taimyr Peninsula) with laboratory IP measurements on 37 rock samples from the same deposit. The samples differed in composition, degree of alteration, type of electron-conductive minerals (pyrite, graphite) and their distribution in the rock. For representative samples of the collection mineralogical and micro-computed X-ray tomography (μ-CT) studies were conducted. This allowed to determine the features of the mineral composition and structure of the samples, as well as to obtain a quantitative characteristic of electron-conductive minerals (pyrite and graphite). According to field and laboratory IP data the relaxation time distributions (RTD) have a similar shape for the same types of rocks. Based on the μ-CT data and the Maxwell-Garnett model, the RTD of the samples were calculated. For some of samples found a good agreement between the CT-based and the IP-based RTD. For others to obtain a satisfactory agreement between the CT-based and IP-based RTD it is necessary to assume that a certain number of pyrite inclusions are passivated or have a flattened shape. The revealed contradiction can be explained by the limited applicability of granular models for well-cemented, low-porosity rocks. This demonstrates the necessity to create an IP model of the rock with the inclusions of electron-conductive minerals that incorporates the structural features of low-permeability capillary media.